Plural rate burner with flame enhancement

ABSTRACT

A burner produces an outward extending flame at a high rate and an upward extending flame at a low rate. Facilities are provided for enhancing the entrainment of air in both the outward extending flame and the upward extending flame.

United States Patent Katchka et al.

[ July '23, 1974 PLURAL RATE BURNER WITH FLAME ENHANCEMENT Inventors:Jay R. Katchka, Cypress; Fred W.

Hendrick; Michael E. Egger, both of Long Beach, all of Calif.

Robertshaw Controls Company, Richmond, Va.

Filed: June 15, 1973 Appl. No.: 370,494

Assignee:

References Cited UNITED STATES PATENTS 12/1957 Beck 431/80 X 3,405,99910/1968 Riehl 431/285 X 3,516,773 6/1970 Rosenberg et a1. 431/2843,561,901 2/1971 Jackson et a1. 431/284 3,754,853 8/1973 Katchka et a1431/285 Primary Examiner-Edward G. Favors Attorney, Agent, orFirmAnthony A. OBrien [5 7] ABSTRACT A burner produces an outwardextending flame at a high rate and an upward extending flame at a lowrate.

Facilities are provided for enhancing the entrainment of air in both theoutward extending flame and the upward extending flame.

8 Claims, 6 Drawing Figures i 48 r, v r

I so 1 PATENTED M2319" 3, 825. 398

sum 10F 2 FIG. I

FIG. 2

' i (I 60 2 5e 58 42\ 62 72 I 48 I3 i 22 PATENTEU -2 74 SHEET 20F 2BACKGROUND OF THE INVENTION 1. Field of the Invention 1 The inventionrelates to burners for gaseous fuel and in particular to burners foroperating at more than one rate. I I

2. Description of the Prior Art There are number of prior art burners,as exemplified by U.S. Pat. No;'3,405,999, which-can be operated at morethan one rate. Prior art plural rate burners produce acceptable flameswhen burning natural gas; however, some burners have not providedsuitable blue flames when burning propane gas, or the like, due to thehigher BTU per cubic foot content of propane gas and the higherproportional air mix requirement;

SUMMARY OF THE INVENTION The invention is summarized in that a burnerfor operating at both low and high rates includes a burner member havingan inlet for receiving gas and a port for projecting gas in a firstdirection such that during a high rate of ope ration a high rate flameextending for at least a predetermined distance along the firstdirection is produced and during a low rate of operation a low rateflame deviating from the first direction in less than said predetermineddistance to a second direction transverseto the first direction isproduced, a first spreader spaced in the first direction from the burnermember in the path of the high rate flame for enhancing-the buming ofthe gas in the high rate flame, a second spreader spaced in the seconddirection from the port and having an Opening for allowing passage ofthe low rate flame, and means disposed within the opening fordispersingthe low rate flame to enhance the burning of the ga'sin the low rateflame. H

An object of the invention is the construction of a plural rate burnerhaving enhanced flame characteristics at a low rate of operation. v I

Another object of the invention is to providea plural rate burnersuitable for operation on high-heatgenerating-capacity gaseous fuels,such as propane gas.

tion will become apparent from the following description of thepreferred embodiment with the drawings. e 4

' BRIEF DESCRIPTION OF TI-IE DRAWINGS: FIG. l.is a elevation view incross section of a burner apparatus in accordance with the invention andillustrating a low rateof operation.

FIG. 2 is a elevation view with parts broken away il taken inconjunction lustrating a high rate operation of the burner apparatusshown in FIG, 1. I 1

FIG. 3 is a top view of a lower'flame spreader burner apparatus shown inFIGS. 1 and 2. r

no. 4 is a perspective view, partially brokerifaway of the lower flamespreader'shown in FIG; 3. FIG. 5 is atop view of an upper flame spreaderof the bumer apparatus shown in FIGS. 1 and 2.

FIG. 6 is a perspective view spreader'shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT.

of the upper flame rate gaseous supply facilities (not shown) such asthe fuel control device disclosedin U.S. Pat. application Ser. No.98,246 by Jay R..- Katchka and Henry C. Braucksiek filed on Dec. 15,.1970, now US. Pat. No. 3,762,639, issued Oct..2,,l973.

The annular burner member 16 has an outer tubular section 12 and aninner tubular'section 14 which form an'annular chamber' IS. The tubularsections 12 and 14 are coaxial with the upper ends joined and with alower flanged portion20 of the inner tubular section joined to the lowerend of the outer tubular section 12.- A fitting 22-is secured within anopening 24 in the outer tubular section 12 to form an inlet to thechamber 18. A plurality of circumferentially-spaced and outwardfacingburner ports 26 are formed in the outer tubular section 12 while asingle inward and upward directed burner port 28 is formed in a deformedportion 30 of the inner tubular section 14. Theouter tubular section 12is generally conical so that the annular chamber 18 is gradually reducedin cross section toward the upper end. T The tubular support 32 issuitably secured to a bottom plate 34 attached to the annular burnermember 16 and has upper slotted spring portions 36 with dimples 38mating with a groove 40 in the flame sensing element 42. The'element 42is supported along a vertical axisf of the annular burner member 16 andextends above the annular burner member 16 such that upward extendingflames from the ports 26 curving inward 5 ofthe' above theannular'member 16 impinge upon the element 42. The flame sensing elementis any suitable thermo-responsive device, such as a thermocouple, whichcan be used to operate safetyfacilities, such as a magnetic safety valve(not shown), to prevent release of hazardous gas in the event that theflame of the burner is extinguished by air drafts, loss of fuel, etc.Openings 44 are formed-in'the bottom plate 34 and are sufficiently sizedto supply adequate air for mixing with gas from the port-28.

The lower "flame spreader 13, shown in FIGS. 3 and 4, has downward bentleg portions 46 extending from an upward flaring frusto-cone portion 48.Tabs 50 are provided on the leg portions 46and are attached, as iI-lustrate'd in FIG. 2, to the outer tubular. section 12 below the ports26, so that the frusto-cone portion 48 is in the path of gas flamesextending outwardly from the burner ports 26. An opening 52 between theftUStO cone portion 48 and the outer tubular section 12 is sufficientlylarge to supply-adequate air for mixing with gasfrom the ports 26.

The upper flame spreader 1s, shown-in FIGS; Sand 6, has an annularplate-like portion 56I'connected by spokes 5 8 to a collar 60 which isattached to the outer tubular section 12 above the burner ports 26, asillustrated in FIG. 2, so that the plate-like portion 56 is disposedabove thepath of gas flames extending outward 64 with enlarged headportions'66 extend inward from the annularportion 56 into the openings62. I

The shield 70 is frustro-conically" formed'and is secured to the upperflame spreader 15 by outward bent tabs 72 extending through the openings62. A-spa'ced with propane to lproduce acceptable blue flames frompropane gas. At the low rate of operation,

top 74 is bent horizontally from an upward extending leg76 of the shield70 and secured in position-by inwardlybent tabs 78from upward extendinglegs 80 from'the shield 70; a

The operation of theplural rate burner at a low rate is illustrated inFIG. 1. With a relatively low pressure gaseous fuel supplied to theinlet fitting 22 and chamberl8 of theannul'anburner member 16,flames'sustained by fuel exiting through ports '26 extendupward throughthe openings 62 in the upper spreader member 15. The tabs 64 and headportions 66, shown in FIGS. 5 and 6, disperse the upward extendingflames to enhance the entrainment of air with the burning fuel and toeliminate yellow flames and produce acceptable blue flames. The lowrateflames passing through the openings 62 converge inward over the topof the annular burner- 16 toward the axis of ithe annular burner member16 to impinge upon the flame sensing element 42. The shield 70 protectsthe low rate flames from being extinguished by a draft :of air or.0thersimilar disturbance. The spacing of the'top 74 from the shield 70 by thelegs 76 and 80 provides adequate ventilation for the flame inpinginguponthe sensing element 42.

At the high rate of operation illustrated in FIG. 2, the pressure of thefuel within the annular burner member 116 is sufficient to direct flamesin a generally horizontal direction outward from the ports 26 againstthe frustoconical portion 48 of the'lower flamespreader 48. Initially,the outward extending flame is-confined below the plate-like portion 56of the upper flame spreader ber 16 supplies air for the high rateflames. The frustoconical portion 48 spreads and disperses the burningfuel in the outward extending flames and enhances the mixtureof fuelwith airto improve combustion.

Also at the high rate of operation, flame from the burner port 28impinges on the flame sensing element 42 to maintain the element 42 inits operated condition. At the low rate of operation, the flamegenerated by the burner port 28 is insignificant relative to the flamefrom the much larger and more numerous 'ports 26. and hence is notillustrated in FIG. I.--

on particular advantage of the burner apparatus is that it can beemployed in a system utilizing liquid propane gas. Propane gas has amuch higher BTU per cubic foot content than commonly used natural gas.At the high rate of operation, the frusto-conical portion 48 in the pathof the outward extending flame together with the opening 52 supplyingair produce sufficient air the, tabs 64 and head portions 66 extendinginto the openings62 together with the supplyof air from the opening 52provide adequate mixing of air with the low rate flame to produce blueflames. Thus, the yellow flames normally associated with the standby orlow rate operation ofnon-aerated burners for propane gas is eliminated.

Since many variations, modifications and changes in detail can be madeto the present embodiment, it is intended that allmatter contained inthe foregoing description'or'sh'own on the accompanying drawings shallbe interrupted as illustrative and not in a limiting sense.

Whatis claimed is: 1. A burner apparatus for operating at both low andhigh rates comprising i a burner member having an inlet for receivinggaseous fuel and a port for'projecting non-aerated gaseous fuel inafirst'direction such that during a high rate of operation a high rateflame extending for at least a predetermined distance along the firstdirection is produced and during a low rate of operation for enhancingthe burning of the gaseous fuel in the "high rate flame,

a second spreader spaced in the second direction from the port andhaving an opening for allowing vpassage of the low rate flame, and

means disposed within the opening for. dispersing the low-rate flame toenhance the burning of the gaseous fuelin the low rate flame.

2. A burner apparatus for operating at both low and high ratescomprising i a burner member'having an inlet for receiving gas and aport for projecting gas in a first direction such that during a highrate of operation a high rate flameextending for at least apredetermined distance along the first direction is produced and duringa low rate of operation a low rate flame deviating from the firstdirection in less than said prede- 1 termined distanceto a seconddirection transverse to the first direction is produced, a firstspreader spaced in the first direction from the burner member in thepath of the high rate flame from the port and having an opening forallowing in the path of the low rate a burner member having an inlet forreceiving gas and a plurality of spaced ports for projecting gas in asubstantially horizontal direction such that during a high rate ofoperation a high rate flame extending for at least a predetermineddistance along the horizontal direction is produced and during a lowrate of operation an upward extending flame deviating from thehorizontal direction in less than said predetermined distance isproduced,

a first spreader spaced in the horizontal direction from the burnermember in the path of the high rate flame for enhancing the burning ofthe gas in the high rate flame,

a second spreader spaced above the plurality of ports and having anopening for allowing passage of the low rate flame,

means disposed within the opening for dispersing the low rate flame toenhance the burning of the gas in the low rate flame.

4. A burner apparatus for operating at both low and high ratescomprising a burner member having an inlet for receiving gas and a portfor projecting gas in a first direction such that during a high rate ofoperating a high rate flame extending for at least a predetermineddistance along the first direction is produced and during a low rate ofoperation a low rate flame deviating from the first direction in lessthan said predetermined distance to a second direction transverse to thefirst direction is produced,

a first spreader spaced in the first direction from the burner member inthe path of the high rate flame for enhancing the burning of the gas inthe high rate flame,

a second spreader spaced in the second direction from the port andhaving an opening for allowing passage of the low rate flame,

means disposed within the opening for dispersing the low rate flame toenhance the burning of the gas in the low rate flame,

said second spreader including a horizontal plate-like portion, and

said dispersing means including a tab projecting from the plate-likeportion into the opening.

5. A burner apparatus as claimed in claim 4 wherein the tab has anenlarged head portion within the opening. 6. A burner apparatus foroperating at both high and low rates comprising a hollow annular memberdisposed about a vertical axis and having a plurality of spaced outwardfacing burner ports such that during a high rate of operation outwardextending flames are produced' a second spreader annularly'disposedabout the annular member above the burner ports and having a pluralityof openings adjacent the annular member for allowing passage of theupward extending flames, and

means disposed in each of the openings for dispersing the upwardextending flames to promote the buming of the upward extending flames.

7. A burner apparatus as claimed in claim 6 which includes a flamesensing element,

means for mounting the flame sensing element along the vertical axisabove the hollow annular member,

means for directing the upward extending flame toward the flame sensingelement after passing through the openings, and

an inward facing port in the hollow annular member for directing a flameagainst the flame sensing element during operation at the high rate.

8. A burner apparatus for operating at both high and low ratescomprising a hollow annular member disposed about a vertical axis havingan inlet for receiving gas and a plurality of spaced outward facingburner ports such that high rate streams of burning gas are projectedradially outward from the annular member and low rate streams of burninggas are projected upward along the outer surface of the annular memberand convergent toward the axis over the top of the annular member, a

a first spreader having an upward flaring frusto-cone portion disposedabout the annular member in the outward paths of the-high rate streamsand leg portions mounting the second spreading member on the annularmember below the outward facing burner ports,

said first spreader having an opening between the frusto-cone portionand the annular member,

a second spreader mounted on the annular member and having a plate-likeportion spaced above the outward facing burner ports,

said plate-like portion having a plurality of openings adjacent theannular member for passing the low rate streams of burning gas,

a flame sensing element,

means for mounting the flame sensing element on the vertical axis abovethe annular member in the path of the convergent low rate streams,

said annular member having an inward facing burner port for projecting astream of burning gas against the flame sensing element during operationat the high rate, and

a plurality of projections each having an enlarged head portionextending into each of the openings in the plate-like portion fordispersing the low rate streams to enhance the burning of the low ratestreams.

' a at

1. A burner apparatus for operating at both low and high ratescomprising a burner member having an inlet for receiving gaseous fueland a port for projecting non-aerated gaseous fuel in a first directionsuch that during a high rate of operation a high rate flame extendingfor at least a predetermined distance along the first direction isproduced and during a low rate of operation a low rate flame deviatingfrom the first direction in less than said predetermined distance to asecond direction transverse to the first direction is produced, a firstspreader spaced in the first direCtion from the burner member in thepath of the high rate flame for enhancing the burning of the gaseousfuel in the high rate flame, a second spreader spaced in the seconddirection from the port and having an opening for allowing passage ofthe low rate flame, and means disposed within the opening for dispersingthe low rate flame to enhance the burning of the gaseous fuel in the lowrate flame.
 2. A burner apparatus for operating at both low and highrates comprising a burner member having an inlet for receiving gas and aport for projecting gas in a first direction such that during a highrate of operation a high rate flame extending for at least apredetermined distance along the first direction is produced and duringa low rate of operation a low rate flame deviating from the firstdirection in less than said predetermined distance to a second directiontransverse to the first direction is produced, a first spreader spacedin the first direction from the burner member in the path of the highrate flame for enhancing the burning of the gas in the high rate flame,a second spreader spaced in the second direction from the port andhaving an opening for allowing passage of the low rate flame, meansdisposed within the opening for dispersing the low rate flame to enhancethe burning of the gas in the low rate flame, a flame sensing elementspaced from the port beyond the dispersing means in the path of the lowrate flame, and said burner member having a second port for projectinggas against the flame sensing element when the burner is operating atthe high rate.
 3. A burner apparatus for operating at both low and highrates comprising a burner member having an inlet for receiving gas and aplurality of spaced ports for projecting gas in a substantiallyhorizontal direction such that during a high rate of operation a highrate flame extending for at least a predetermined distance along thehorizontal direction is produced and during a low rate of operation anupward extending flame deviating from the horizontal direction in lessthan said predetermined distance is produced, a first spreader spaced inthe horizontal direction from the burner member in the path of the highrate flame for enhancing the burning of the gas in the high rate flame,a second spreader spaced above the plurality of ports and having anopening for allowing passage of the low rate flame, means disposedwithin the opening for dispersing the low rate flame to enhance theburning of the gas in the low rate flame.
 4. A burner apparatus foroperating at both low and high rates comprising a burner member havingan inlet for receiving gas and a port for projecting gas in a firstdirection such that during a high rate of operating a high rate flameextending for at least a predetermined distance along the firstdirection is produced and during a low rate of operation a low rateflame deviating from the first direction in less than said predetermineddistance to a second direction transverse to the first direction isproduced, a first spreader spaced in the first direction from the burnermember in the path of the high rate flame for enhancing the burning ofthe gas in the high rate flame, a second spreader spaced in the seconddirection from the port and having an opening for allowing passage ofthe low rate flame, means disposed within the opening for dispersing thelow rate flame to enhance the burning of the gas in the low rate flame,said second spreader including a horizontal plate-like portion, and saiddispersing means including a tab projecting from the plate-like portioninto the opening.
 5. A burner apparatus as claimed in claim 4 whereinthe tab has an enlarged head portion within the opening.
 6. A burnerapparatus for operating at both high and low rates comprising a hollowannular member disposed about a vertical axis and having a plurality ofspaced outward facing burner ports such that during a high rate ofoperation outward extending flames are produced and during a low rate ofoperation upward extending flames are produced, a first spreaderannularly disposed about the annular member in the paths of the outwardextending flames for promoting the burning of the outward extendingflames, a second spreader annularly disposed about the annular memberabove the burner ports and having a plurality of openings adjacent theannular member for allowing passage of the upward extending flames, andmeans disposed in each of the openings for dispersing the upwardextending flames to promote the burning of the upward extending flames.7. A burner apparatus as claimed in claim 6 which includes a flamesensing element, means for mounting the flame sensing element along thevertical axis above the hollow annular member, means for directing theupward extending flame toward the flame sensing element after passingthrough the openings, and an inward facing port in the hollow annularmember for directing a flame against the flame sensing element duringoperation at the high rate.
 8. A burner apparatus for operating at bothhigh and low rates comprising a hollow annular member disposed about avertical axis having an inlet for receiving gas and a plurality ofspaced outward facing burner ports such that high rate streams ofburning gas are projected radially outward from the annular member andlow rate streams of burning gas are projected upward along the outersurface of the annular member and convergent toward the axis over thetop of the annular member, a first spreader having an upward flaringfrusto-cone portion disposed about the annular member in the outwardpaths of the high rate streams and leg portions mounting the secondspreading member on the annular member below the outward facing burnerports, said first spreader having an opening between the frusto-coneportion and the annular member, a second spreader mounted on the annularmember and having a plate-like portion spaced above the outward facingburner ports, said plate-like portion having a plurality of openingsadjacent the annular member for passing the low rate streams of burninggas, a flame sensing element, means for mounting the flame sensingelement on the vertical axis above the annular member in the path of theconvergent low rate streams, said annular member having an inward facingburner port for projecting a stream of burning gas against the flamesensing element during operation at the high rate, and a plurality ofprojections each having an enlarged head portion extending into each ofthe openings in the plate-like portion for dispersing the low ratestreams to enhance the burning of the low rate streams.